Chronic sinusitis is a medical condition that affects the lives of millions of people every year. In fact, it has been estimated that chronic sinusitis results in 18 million to 22 million physician office visits per year in the United States. Chronic sinusitis refers to inflammation of the paranasal sinuses that lasts for three months or more or that occurs frequently. The condition can be very debilitating, often causing headaches, facial pain, excessive nasal drainage, difficulty breathing through the nose and other symptoms, and often making certain activities such as flying in an airplane very painful. The overall costs to society of chronic sinusitis are enormous, in terms of medical costs, missed days of work, etc.
The paranasal sinuses are air spaces behind the bones of the upper face, between the eyes and behind the forehead, nose and cheeks. On each side of the face there is one set of frontal sinuses (in the forehead), maxillary sinuses (in the cheek bones), ethmoid sinuses (between the eyes) and sphenoid sinuses (farther back behind the eyes). The frontal, maxillary and sphenoid sinuses are all connected to, and drain into, the nasal cavity via openings called ostia (“ostium” singular). The nasal cavity and paranasal sinuses are made of bone covered with mucous tissue, and the mucous tissue has small, hair-like projections called cilia, which move together to sweep mucus through and out of the sinuses as a kind of filter. When the mucosal tissue of the sinuses becomes inflamed, often due to infection, it sometimes swells and can block one or more ostia, thus preventing the movement of mucus from the sinuses to the nasal cavity and thus causing blockage, pressure build-up, and the symptoms of sinusitis. This blockage can sometimes last for long periods of time or recur again and again, causing a great deal of discomfort.
One of the ways to treat sinusitis is by restoring the flow of mucus through and out of the sinuses via the openings (ostia) into the nasal cavity. Typically, the initial therapy attempted in treating sinusitis is drug therapy and nasal sprays—anti-inflammatory agents to reduce inflammation of the mucosal tissue and antibiotics to treat infection. A large number of patients do not respond to nasal spray/drug therapy, however. Patients with chronic or recurring sinusitis may and do not respond to drug therapy may then decide to undergo a surgical procedure.
One form of surgical procedure for treating chronic sinusitis is a called Functional Endoscopic Sinus Surgery (“FESS”). In FESS, a rigid endoscope is inserted into the nose, and a surgeon uses one or more rigid instruments, such as shavers and graspers, to remove diseased or hypertrophic mucosal tissue and bone and in some cases enlarge the ostia of the sinuses to attempt to “open up” and restore normal drainage of the sinuses. These FESS procedures are successful in many cases but do have a number of significant drawbacks. For example, general anesthesia is required for a FESS procedure. Also, because significant amounts of soft tissue and bone are typically removed, FESS can cause significant bleeding and post-operative pain, and thus recovery from surgery can be painful and take many days or even weeks. Because FESS procedures are often associated with significant postoperative bleeding, nasal packing is frequently placed in the patient's nose for some period of time following the surgery. Such nasal packing can be uncomfortable and can interfere with normal breathing, eating, drinking etc. This packing often must be removed and replaced, which can be very uncomfortable. Scar tissue may also have to be removed in the physician's office, in a procedure called a “debridement,” which can also be very painful. Also, some patients remain symptomatic even after multiple FESS surgeries. Additionally, some FESS procedures are associated with risks of iatrogenic orbital, intracranial and sinonasal injury. Many otolaryngologists consider FESS an option only for patients who suffer from severe sinus disease (e.g., those showing significant abnormalities under CT scan). Thus, patients with less severe disease may not be considered candidates for FESS and may be left with no option but drug therapy. One of the reasons why FESS procedures can be bloody and painful relates to the fact that instruments having straight, rigid shafts are used. In order to target deep areas of the anatomy with such straight rigid instrumentation, the physician needs to resect and remove or otherwise manipulate any anatomical structures that may lie in the direct path of the instruments, regardless of whether those anatomical structures are part of the pathology.
As an alternative to traditional FESS procedures, the assignee of the present application has invented a number of less invasive/less traumatic systems, devices and methods for treating chronic sinusitis by expanding openings between the nasal cavity and the paranasal sinuses using an expandable dilation device. In some instances, these and other methods for treating sinusitis or other conditions may involve advancing one or more devices into the nasal cavity and/or a paranasal sinus via a guide device, such as a guide catheter. Because the anatomy of the nasal cavity, the paranasal sinuses and the openings between the two is very complex, small and tortuous, and because damage to mucosal tissue in the nasal cavity and sinuses may cause post-operative pain and bleeding, a need exists for guide devices that are relatively easy to use in this anatomy and are as atraumatic as possible. The present disclosure addresses these and other needs.